长江中游洪灾形成的地学分析  

GEO-SCIENTIFIC ANALYSIS OF THE FLOOD CALAMITY IN THE MIDDLE REACHES OF CHANGJIANG RIVER

作　　者：李长安[1] 陈国金[2] 皮建高 

机构地区：[1]中国地质大学地球科学学院,武汉430074 [2]湖北省水文地质工程地质大队,荆州434100 [3]湖南省第二水文队,长沙410014

出　　处：《第四纪研究》2003年第6期675-682,共8页Quaternary Sciences

基　　金：国家自然科学基金 (批准号 :40 1 72 0 61 )资助项目;国家基础研究快速反应项目;中国地质调查局大调查项目 (项目号 :1 9991 2 3 0 0 0 3 0 1 4)

摘　　要：地质地貌条件是长江中游洪灾形成的背景条件 ,近代洪水位不断上升是人 -地不和谐作用下流域环境系统演化的结果。人类作用导致的多流归槽改变了长江中游河流的地貌过程和水文特性 ,致使洪水过程显著 ;大堤修筑导致堤外河漫滩出现泥沙加积 ,自 1 65 0年荆江大堤合拢以来 ,边滩总体淤积厚度为 2 .8～ 1 1 .0m ,平均淤积速率 1 2 .5 4～ 2 5 .64mm/a ;围湖造田导致江汉 -洞庭平原蓄洪空间减少和“小水大灾”局面的形成 ;漫滩筑堤围垸严重影响了长江行洪 ,仅荆江段就有围筑的民垸 84个 ,总面积为 4895 .95km2 ,民垸面积是泄洪面积的近 9倍。因此 ,在认识自然规律的基础上 ,正确协调人 -地 -水关系 ,重建良性循环的流域环境系统 ,是解决长江中游的水患的根本出路。The regional landforms and the second Newcazhaysian tectonic sinking zone are the geologic background forming flood in the middle reaches of Changjiang River. The ground subsidence of Jianghan-Dongting plain with a speed of 5～10 mm/a, complicated geologic tectonics, geomorphology and lithology along the Jinjiang river play an important role in the formation of flood calamity. The rising of the flood level of Jingjiang and the increased flood calamity threatening are the result of disharmony between human activities and geologic function. (1)Some streams conflux led by human activities changes the landforms process and the hydrology in the middle reaches of Changjiang River. Because the changing amplitude of the water level and discharge of the single river is big and it doesn′t drain off large quantity of water from upper reaches, the flood progress is very remarkable. (2) The big dike building causes the Jingjiang flood level to rise continuously. Before the big dike was constructed, the mud and sand of Changjiang River was overflowing and silting up in Jianghan plain, the ground subsidence and the deposition of the mud and sand were placed in opposite equilibrium. After the big dike,Changjiang River is controlled between two dikes, the sediment space of mud and sand changed from the face form to the line form, causing the accumulation of mud and sand in the concave flood plain of the dike outside. Since Jingjiang dike was gathered together in 1650, the total thickness of the marginal bank is 2.8 to 11.0 m, the sedimentation velocity is 12.54 ～25.64 mm /a, the height of the channel bar is 5 ～10 m in general. The rising concave flood plain raised the flood level. At the same time, the ground inside the dike lowers continuously because of the tectonic subsidence (5 ～10 mm/a ) and lacking the compensation of the mud and sand. As a result, the height difference of the flood level between inside and outside dikes adds up continuously, the height difference is 8～16 m at present. (3) Reclaiming land around

关 键 词：洪水灾害 地学环境 人-地关系 长江中游地区 

分 类 号：P426.616[天文地球—大气科学及气象学]